Boating New Zealand - May 2018

36 Boating New Zealand

yacht upright when not generating RM from the foils (under

tow, low speed manoeuvres pre-start etc) by lowering the foil

arms under the hull.

he software controlling the foil cant system is open, but

tightly speciied, and warrants an article of its own by someone

more qualiied than me to comment on it. he rule speciies the

foils may not generate net downforce, efectively prohibiting

using the windward foil to ‘hook in’ and augment the righting

moment of the leeward foil.

Hull shape is free other than a maximum beam of 5.0m and

a 4.0m beam measurement at the transom, a 4.1m separation of

the foil pivot points (which could be ‘buried’ deeper in a wider

hull), plus a couple of measurements right forward to put a

restriction on scow bows.

So there is signiicant scope for hull shape diferences in

sub-foiling conditions, trading a slippery, easily-driven form that

gets up to foiling speeds sooner with less drag but also less RM

than a more powerful but higher resistance form, which could

harness the rig better and generate more forward thrust.

A tricky balance, as transitions on to the foils will be a make-

or-break aspect of the racing.

Mainsails will have two ‘skins’ attached using luf tracks

on each side of the D-section mast. his efectively forms a

wingsail, but without the complexity of the solid wings seen

previously. he ability to lower the mainsail means control can

be maintained when docking in/out of the bases.

Before committing to the design the ETNZ/LR design team

built a prototype rig on a 22ft trimaran (non-foiling!) and

sailed it on the Waitemata. BNZ

ABOVE The recently-published Rule precisely specifies rig

design and sail plan.

Note: Numbers of each allowed in brackets. Modifications allowed to only one hull (protocol amendment

pending a second hull). Defender has an allowance of 12 mains and 35 headsails.

PARTS OF THE AC75

AMERICA’S CUP

KEY DATES

June 30, 2018:

Entries for Challengers close

August 31, 2018:

Location of the America’s Cup Match

and The PRADA Cup confirmed

August 31, 2018:

Specific race course area confirmed

December 31, 2018:

Late entries deadline

March 31, 2019:

Boat 1 can be launched

2nd half of 2019:

2 x America’s Cup World Series

Preliminary Events

February 1, 2020:

Boat 2 can be launched

During 2020:

3 x America’s Cup World Series

Preliminary Events

December 10-20, 2020:

America’s Cup Christmas Race

January and February 2021:

The PRADA Cup Challenger

Selection Series

March 2021:

The America’s Cup Match

SPECIFIED DESIGN SUPPLIED PARTS OPEN DESIGN AND MANUFACTURE

Mast Tube (3) Foil Arms (4) Hull (2) Rudder upper/lower (4/4)

Foil Cant System (2) Foil Wings (6)Foil Flaps (20)

Mast standing Rigging (3) Mainsails (10) Headsails (29 – Jibs and CZ)